The invention relates to a tool for helically coiled wire inserts and, more particularly, to a notch-forming extraction tool for use in association with helically coiled inserts.
Tools for the removal of helically coiled wire inserts are well known. Generally, these tools have a tapered blade with a pair of knife edges that are driven into the inner diameter threads of the insert. Such as tool is described in U.S. Pat. No. 6,171,040. When using these tools to extract an insert, however, the insert and the parent material surrounding it is often permanently damaged.
Another type of removal tool for helically coiled wire inserts is described in U.S. Pat. No. 4,553,303 and includes a mandrel having a threaded lead portion and a pivotable pawl inserted in a groove below the threaded portion so that the pawl can engage a notch in the trailing end of the insert in order to extract the insert from the tapped hole. This pivotable pawl automatically engages the insert when the mandrel is pulled back, allowing the mandrel to extract the insert. Although this known extraction tool does not damage the parent material of the insert, it is a relatively complicated design and suffers from increased risks of malfunction. Further, because each insert requires a tool of complimentary size, a set of tools taught by the aforementioned patent is relatively expensive.
An improved extraction and adjustment tool for helically coiled wire inserts is described in co-pending U.S. patent application Ser. No. 09/596,035, which is incorporated herein by reference. While the extraction and adjustment tool described therein is believed to be a significant advancement over the prior art, it is particularly suited for use with inserts already having a notched coil end.
An extraction tool for helically coiled wire inserts includes a mandrel with a threadless lead portion having a stationary tooth for forming a notch in a trailing end of the insert. Upon formation of the notch, the extraction tool can thereafter be utilized for extracting the insert from a tapped hole. The extraction tool may include a handle portion having a bushing for selective reception of a mandrel adapted to fit a particular-size helically coiled wire insert or may be used in association with a power tool to effectuate removal of the insert. Once the extraction tool is inserted into the internal diameter of the insert and a notch is formed, the stationary tooth engages the notch in the trailing end of the insert to extract the wire insert.